Cotter key



1941- J. E. LEMISON 66,

\ COTTER KEY Filed Sept. 14, 1940 Ja .5. 2:2 BY 2 l M Patented Dec. 16, 1941 UNITED STATES PATENT OFFICE COTTER KEY James E. Lemison, Sacramento, Calm, asslgnor of one-half to Arthur S. Shaw, Stockton, Calif.

Application September 14, 1940, Serial No. 356,807

2 Claims.

This invention relates generally to an improvement in cotter keys, and in particular the invention is directed to-and it is my principal object to provide--a self-locking cotter key.

Another object of the invention is to provide a cotter key constructed so that when driven into the receiving hole or bore in a bolt, clevis pin or the like, the initially parallel and engaged legs or shanks of the cotter key spread apart at and adjacent their free ends whereby to facilitate the entry of a spreading tool therebetween.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawing similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a side elevation of one form of my improved cotter key.

Figure 2 is a side elevation of the same in locked position in the key receiving hole or bore of a bolt or the like.

Figure 3 is a side elevation of another form of the device.

Figure 4 is an elevation of the form of the device shown in Fig. 3 in locked position in the key receiving hole of a bolt or the like; the bolt hole including locking lips.

Referring now more particularly to the characters of reference on the drawing, and at present to the form of the invention shown in Figs. 1 and 2,' the cotter key, as usual, includes a pair of legs or shanks, indicated at l and 2, secured together in integral relation at one end by a head or eye E; these shanks being initially mainly parallel and engaged. The shank i adjacent the eye E is deformed laterally outward to provide what may be termed a hump 3.

In use, the key is driven through the key receiving hole or bore 4 of a bolt 5 or the like until the eye E engages the sides of the bolt. The width of the key in the plane of the hump is initially greater than the diameter of hole 4 whereby when the cotter key is forcefully driven into the hole, the hump is depressed or deformed laterally inward toward leg 2, as shown in Fig, 2. When portion 3 is deformed inward, the shank i tends to swing or bend laterally away from shank 2 about point 6, which serves as a fulcrum or pivot. Shank i then diverges from a shank 2 and projects some distance beyond bolt 5, shank I at its outer end separating from shank 2 such distance that the cotter key cannot thereafter accidentally retract from the hole 4. Shank i has also engaged the periphery of hole d at the end opposite eye E.

In inaccessible places where the cotter key cannot readily be reached, no further spreading of the shanks is necessary, as the cotter key will effectively remain in place. If further bending is desired and feasible, the bending tool can be readily inserted between the already separated shanks and the projecting portions thereof bent over.

In the form of the invention shown in Figs. 3 and 4, both shanks id and 2a are deformed laterally outward to provide oppositely extending humps 3a. In this form of the invention, a double locking effect is had when the key is driven into the hole 6 in bolt 5, and in this instance both legs swing or bend apart in opposite directions about point to as the fulcrum or pivot, and therefrom diverge and engage the periphery of the hole at the end opposite eye E.

In Fig. 4, I have also provided the bolt hole 4a with additional means to hold the cotter key in place. At or adjacent the ends of the hole, the diameter thereof is reduced whereby to form annular and radially inwardly projecting flanges or lips l; the humps 3a engaging in the hole 3a adjacent but inwardly of one of said lips. In addition to the frictional or wedging engagement of the bumps in the hole, one of the lips 'i engages between the humps and the eye E and further assures against accidentaal retraction of the cotter key from the hole.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. A cotter key comprising an eye, a pair of shanks projecting from the eye and parallel and initially engaged with each other for the major portion of their length fromtheir outer end, and a resilient hump formed in one leg so that the key at the apex of the hump is of greater width than the diameter of a hole through which the pin is to be placed; the apex of the hump being 2. A cotter key as in claim 1, in which the ape! immediately adjacent the eye and the hump then of the hump is adJacent that end thereof which is sloping toward the outer end of the correspondnearest the eye and the slope from said apex to in: leg whereby spread of said one leg at its outer said corresponding leg is straight and relatively endwillbeminimizeduntllthekeyisiullyin 5 short and is disposed at a small acute angle position in its hole with the eye adjacent one end thereto.

thereof. I l JAMES E. IEMISON. 

